New Axion Searches at Flavor Factories

TL;DR

This paper evaluates the potential of flavor factory experiments like LHCb, BABAR, and Belle-II to detect new axion-like particles that couple to photons and gluons, providing complementary constraints to collider searches.

Contribution

It introduces a novel approach to search for heavy axions at flavor factories, extending the mass range and sensitivity beyond existing collider experiments.

Findings

Current LHCb data sets the best limits for axions between 4.9 and 6.3 GeV.

Future LHCb searches could probe axion decay constants around TeV scales.

BABAR and Belle-II data further constrain axion parameter space.

Abstract

We assess the impact of searches at flavor factories for new neutral resonances that couple to both photons and gluons. These are well motivated by "heavy axion" solutions of the strong CP problem and by frameworks addressing both Dark Matter and the Higgs hierarchy problem. We use LHCb public diphoton data around the Bs mass to derive the current best limit on these resonances for masses between 4.9 and 6.3 GeV. We estimate that a future LHCb dedicated search would test an axion decay constant of O(TeV) for axion masses in the few-to-tens of GeV, being fully complementary to the low mass ATLAS and CMS searches. We also derive the impact of BABAR searches based on Upsilon decays and the future Belle-II reach.